Ischemic heart disease causes mitral regurgitation by the combination of ischemic dysfunction of the papillary muscles, and the dilatation of the left ventricle that is present in ischemic heart disease, with the subsequent displacement of the papillary muscles and the dilatation of the mitral valve annulus.
Dilation of the annulus of the mitral valve prevents the valve leaflets from fully coapting when the valve is closed. Mitral regurgitation of blood from the left ventricle into the left atrium results in increased total stroke volume and decreased cardiac output, and ultimate weakening of the left ventricle secondary to a volume overload and a pressure overload of the left atrium.
US Patent Application Publications 2004/0260393 to Randert et al. and 2004/0127982 to Machold et al. describe techniques using an implant that is sized and configured to attach in, on, or near the annulus of a dysfunctional heart valve. In use, the implant extends either across the minor axis of the annulus, or across the major axis of the annulus, or both. The implant is described as restoring to the heart valve annulus and leaflets a more functional anatomic shape and tension. The more functional anatomic shape and tension are conducive to coaptation of the leaflets, which, in turn, reduces retrograde flow or regurgitation. In some embodiments, the implant is configured to rest at or near a heart valve annulus and apply a direct mechanical force along the minor axis of the annulus to inwardly displace tissue toward the center of the annulus. For some applications, the implant is configured to extend significantly above the plane of the valve, while for other applications, the implant is configured to extend a short distance above the plane of the valve.
U.S. Pat. No. 7,500,989 to Solem et al. describes devices and methods for treating mitral regurgitation by reshaping the mitral annulus in a heart. One device for reshaping the mitral annulus is provided as an elongate body having dimensions as to be insertable into a coronary sinus. The elongate body includes a proximal frame having a proximal anchor and a distal frame having a distal anchor. A ratcheting strip is attached to the distal frame and an accepting member is attached to the proximal frame, wherein the accepting member is adapted for engagement with the ratcheting strip. An actuating member is provided for pulling the ratcheting strip relative to the proximal anchor after deployment in the coronary sinus. In one embodiment, the ratcheting strip is pulled through the proximal anchor for pulling the proximal and distal anchors together, thereby reshaping the mitral annulus.
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The following articles, which are incorporated herein by reference, may be of interest:
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